complement

Definition of complement

(Entry 1 of 2)

1a: something that fills up, completes, or makes better or perfect
The scarf is a perfect complement to her outfit.

b(1): the full quantity, number, or assortment needed or included
… the usual complement of eyes and ears …— Francis Parkman… after several more minutes of waiting, the full complement of runners was sent off by the starter's pistol.— Craig Neff

(2): the whole force or personnel of a ship

c: one of two mutually completing parts : counterpartShe is a kind of complement to me, and we get on famously.— Flannery O'Connor

2: an added word or expression by which a predication is made complete (such as president in "they elected him president" and beautiful in "he thought her beautiful")

3a: the angle or arc that when added to a given angle or arc equals a right angle in measure

b: the set of all elements that do not belong to a given set and are contained in a particular mathematical set containing the given set

c: a number that when added to a certain number of the same sign yields a number with the digit 1 as the significant digit farthest to the left and the digit 0 in every other digit place—used especially in assembly language programming

4: the musical interval required with a given interval to complete the octave

5: the thermolabile group of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (such as bacteria and foreign blood corpuscles)

Synonyms for complement

Is it complement or compliment?

Today there is no overlap between the meanings of complement and compliment, as either nouns or verbs, but their similar spellings and pronunciations make them prime candidates for confusion. Despite the difference in their meanings, both complement and compliment have roots in the Latin word complēre which means “to complete.” Complement remains true to that origin in its spelling and in its meanings that have to do with completing or completion. Keep that connection in mind and there should be no question as to whether complement or compliment is the correct word to use in a given context.

Examples of complement in a Sentence

Noun

With the loss of just one American and four Japanese carriers, including their complements of aircraft and many of their superbly trained fliers … , Midway … put the Japanese navy at a disadvantage from which it never recovered.— David M. Kennedy, Atlantic, March 1999Exact observation of the outer world was the complement to a literal reading of Scripture.— Garry Wills, Under God, 1990The usual complement of Kremlin guards was about, one company of infantry with light arms.— Tom Clancy, Red Storm Rising, 1986His faults are accepted as the necessary complement to his merits.— W. Somerset Maugham, Moon and Sixpence, 1919
The scarf is a perfect complement to her outfit.
a full complement of farm animals
her usual complement of attendants
a ship's complement of officers
“President” in “they elected her president” and “to work” in “he wants to work” are different kinds of complements.

Verb

Carrots often work even better than sticks, so I propose a skinny subsidy to complement the fat tax.— Jonathan Rauch, Atlantic, December 2002The love of Bottom's bottomless vision at least complements, if it does not transcend, the rational love of Theseus.— Frank Kermode, Shakespeare's Language, 2000 … his ice-blue Appalachian eyes glint through horn-rimmed glasses, which complement his salt-and-pepper beard.— Henry Louis Gates, Jr., New Yorker, 19 June 1995 … lively photographs, illustrations and cartoons designed to complement the meanings of the poems and give a leg-up to the imagination.— Carol Ann Duffy, Times Literary Supplement, 4-10 Dec. 1987
The shirt complements the suit nicely.
a delicious dinner complemented by a splendid dessert
The soup and salad complement each other well.

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'complement.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Medical Definition of complement

3: the thermolabile group of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (as bacteria and foreign blood corpuscles)